"Полет сквозь звезды" на VB.NET

Public Class Form1
    Dim st(500) As Point
    Private WithEvents timer As New Timer With {.Interval = 20}
 
    Private context As BufferedGraphicsContext
    Private grafx As BufferedGraphics
    Private rnd As New Random
    Private screen As Rectangle 'Область вывода
    Private speed As Integer = 5 'Скорость разлёта
 
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Me.WindowState = FormWindowState.Maximized
        screen = New Rectangle(-Me.ClientRectangle.Width / 2, -Me.ClientRectangle.Height / 2, Me.ClientRectangle.Width, Me.ClientRectangle.Height)
 
        For i As Integer = 0 To st.Length - 1
            st(i) = New Point(rnd.Next(screen.X, Math.Abs(screen.X)), rnd.Next(screen.Y, Math.Abs(screen.Y)))
        Next
 
        context = BufferedGraphicsManager.Current
        context.MaximumBuffer = New Size(Me.Width + 1, Me.Height + 1)
        grafx = context.Allocate(Me.CreateGraphics(), New Rectangle(0, 0, screen.Width, screen.Height))
        timer.Enabled = True
    End Sub
 
    Private Sub Tick(sender As Object, e As EventArgs) Handles timer.Tick
        DrawStars(grafx.Graphics)
        grafx.Render(Graphics.FromHwnd(Me.Handle))
    End Sub
 
    Private Sub DrawStars(g As Graphics)
        g.TranslateTransform(Math.Abs(screen.X), Math.Abs(screen.Y))
        g.Clear(Color.Black)
        Dim z As Decimal
        For i As Integer = 0 To st.Length - 1
            z = Math.Sqrt(Math.Pow(st(i).X, 2) + Math.Pow(st(i).Y, 2))
            z = (z + speed) / z
            st(i).X *= z : st(i).Y *= z
            g.FillEllipse(Brushes.White, New Rectangle(st(i).X, st(i).Y, 2, 2))
            If Not screen.Contains(st(i)) Then
                st(i) = New Point(rnd.Next(screen.X, Math.Abs(screen.X)), rnd.Next(screen.Y, Math.Abs(screen.Y)))
            End If
            'Me.Text = st(i).ToString()
        Next
        'g.FillEllipse(Brushes.Blue, -10, -10, 20, 20)
        g.ResetTransform()
    End Sub
 
    Private Sub Form1_Resize(sender As Object, e As EventArgs) Handles Me.Resize
        screen = New Rectangle(-Me.ClientRectangle.Width / 2, -Me.ClientRectangle.Height / 2, Me.ClientRectangle.Width, Me.ClientRectangle.Height)
        context = BufferedGraphicsManager.Current
        context.MaximumBuffer = New Size(screen.Width + 1, screen.Height + 1)
        If grafx IsNot Nothing Then
            grafx.Dispose()
            grafx = Nothing
        End If
        grafx = context.Allocate(Me.CreateGraphics(), New Rectangle(0, 0, screen.Width, screen.Height))
    End Sub
End Class